Comma Korotkova - transmission line speaker cabinet

thingiverse

I'm a fan of audio and 3d printing. For a quite long time I was experimenting with printing ready to use speaker cabinets and always want to proof that 3d printed cabinet can work as good as wooden case. I.e. basically you can find good speakers and print case that will ideally match theese speakers. After all experiments I have an impression that bass reflex cases can be made with paramaters close to wodens ones, but only as ball or egg alike cases. Plastic case with flat pannels and reasonable thinckness can't get desired level of stiffnes and tightness. Ball or egg forms improove things a lot but didn't give same results from print to print and usually still behave little worse than equialent wooden cases. With 3d printing I learned that you should adjust your mind to what is easy for 3d printer and what gives good or better results than classic forms. Good 3d printing design is usually something that is nearly to impossible to build by another means other than 3d printing. Worth to note that such designs can looks really strange for our "square" world. So, after spending dozens of kilograms of plastic and printing lot of different designs I finally come to one, that gives really good results. Thechically this is "transmission line" acoustic design which in some way is perfect match with 3d printing. This is a labirinth design which is ready to use right after print. No supports are required (not plastic waste), nthing to glue, nothing to tune, no any post processing. Just put speaker inside and that's it. These cases are good with PLA and especcially good with Wood PLA. I printed these cases for 3" and 4" speakers. Both are with Fs=75 hz. I not recommend speakers with significantly higher resonance frequency and unlikely you will find with lower. However it is not hard to adopt using source files in FreeCad. Because of assymitric design I recommend to mirrow 2nd speaker during printing as shown on photos. I named this speakers as "Comma Korotkova" because form of outlines from upper right side of speakers reminds me comma character. And Korotkov is my last name :) 3" speaker - http://www.loudspeakerdatabase.com/TangBand/W3-2141 4" speaker - http://www.loudspeakerdatabase.com/Fostex/FF105WK For 3" speaker it might be required to add highpass filters because on 50Hz and yet reasonable volume speaker "jumps out" from its basket and you can hear weird sounds. You can discover maximum reasonable volume on 100Hz because this is another exteremum of of driver movements. For myself I'm using DIY amplifier board with DSP - https://aliexpress.com/item/1005004178491314.html 4" speaker also can be improoved with DSP board but not require any special tuning and little more ballanced out of the box.